In Canada, bum is considered the most appropriate term when speaking to young children, as in Everyone please sit on your bum and we'll read a story. In the United States, bum is not often used much used in this sense (though this may vary from dialect to dialect) except in conscious imitation of British English. The term butt is the most common term in North America except in professional contexts such as medical, legal, and scientific where buttocks is generally used or gluteus maximus, gluteus medius, etc. for the muscles specifically. Glutes is often used in sports medicine and bodybuilding. Ass (originally a dialectal variant of arse) is considered vulgar in North America, whereas backside, behind, and bottom are considered to be non-specific terms.